Multipolar fault current protective switch

ABSTRACT

The switch comprises a summation current transformer unit containing a ground fault current testing part and a release part. Relatively narrow type automatic cutouts or circuit breakers are attached to the unit in juxtaposition thereto, and coupled mechanically and electrically to these parts. Each automatic cutout has, between the input and the output sides, two superposed externally accessible connecting points for interconnection with respective windings of the summation transformer. Each cutout has side walls with openings communicating with the connecting points and providing for insertion of the ends of the respective transformer winding into the cutout and into the connecting points thereof. The unit and the circuit breakers have identical profiles in side elevation and, when bolted together, are mounted in the same switch cabinet.

United States Patent [191 Schmitt et a1.

[ Jan. 15, 1974 MULTIPOLAR FAULT CURRENT PROTECTIVE SWITCH [73]Assignee: Brown, Boveri & Cie AG,

Mannheim, Germany [22] Filed: Feb. 7, 1972 [21] Appl. No.: 223,921

[30] Foreign Application Priority Data Feb. 13, 1971 Germany G 71 05414.3

[52] US. Cl. 335/13, 317/18 D [5]] Int. Cl. HOlh 71/46 [58] Field ofSearch ..335/13, 173, 17; 317/58, 18 D [56] References Cited UNITEDSTATES PATENTS 3,636,482 l/1972 Edmunds 317/18 D 3,436,695 4/1969Dessert 335/13 3,566,189 2/1971 Wilson 317/18 D Primary Examiner-HaroldBroome Attorney-John J. McGlew et al.

[ 5 7 ABSTRACT The switch comprises a summation current transformer unitcontaining a ground fault current testing part and a release part.Relatively narrow type automatic cutouts or circuit breakers areattached to the unit in juxtaposition thereto, and coupled mechanicallyand electrically to these parts. Each automatic cutout has, between theinput and the output sides, two superposed externally accessibleconnecting points for interconnection with respective windings of thesummation transformer. Each cutout has side walls with openingscommunicating with the connecting points and providing for insertion ofthe ends of the respective transformer winding into the cutout and intothe connecting points thereof. The unit and the circuit breakers haveidentical profiles in side elevation and, when bolted together, aremounted in the same switch cabinet.

7 Claims, 3 Drawing Figures MULTIPOLAR FAULT CURRENT PROTECTIVE SWITCHFIELD OF THE INVENTION This invention relates to ground fault currentprotective switches and, more particularly, to a multipolar faultcurrent protective switch formed of a summation current transformer, aunit containing fault current testing and circuit breaker release parts,and narrow type unipolar automatic cutouts or circuit breakers attachedto the unit and coupled mechanically and electrically with the parts.

BACKGROUND OF THE INVENTION A fault current protective switch of thistype is disclosed in German Design Pat. No. 6,607,215, wherein theterminals for the interposition of the winding of the summation currenttransformer are arranged in series. The terminal for the externalconnection is arranged on a part attached to the automatic cutouts andforms cable channels for the shunt lines, while it covers the SUMMARY OFTHE INVENTION It is the objective of the invention to provide amultipolar ground fault current protective switch of the above-mentionedtype with the profile of an automatic cutout or circuit breaker, andwith the use of unipolar automatic cutouts or circuit breakers and witha minimum expenditure for the shunt or cross connection.

In accordance with the invention, this problem is solved in that eachautomatic cutout has, between the input and output sides, two superposedexternally accessible connections or connection points, forinterconnection of a respective winding of the summation currenttransformer. Additionally, openings for the passage of the ends of therespective winding of the summation current transformer are provided inthe side walls of the automatic cutout and in communication with theconnection points.

The upper connecting point can be a terminal with a connecting lughaving a bore and bearing on the wall, and the lower connecting pointcan be the end of a connecting rail or bus designed as a connecting ingwith a bore and extending into the switch, and which is likewise pressedto the apparatus wall. The ends of the summation current transformerwinding can be conducted, in a simple manner, through the openings,placed from the inside through the bore of the respective connectinglug, and be welded or soldered with the latter from the outside.Preferably, the lower connecting points are covered with an insulatingstrip so that only the upper connecting point for the externalconnection remains exposed, so that confusion is not possible.

The summation current unit and the automatic circuit breakers haveidentical profiles in side elevation, whereby they may be securedtogether in side-by-side relation to provide a switch having the profileof an automatic circuit breaker. The circuit breakers and the summationcurrent unit, when thus bolted together, are mounted in the same switchcabinet.

An object of the invention is to provide an improved multipolar faultcurrent protective switch.

Another object of the invention is to provide such a switch including asummation current transformer unit containing a fault current testingpart and a release part, with unipolar narrow-type automatic cutoutsattached to the unit and mechanically and electrically coupled with theparts, and with the unit and the automatic cutouts having identicalprofiles in side elevation for securing together in side-by-siderelation to each other.

A further object of the invention is to provide such a switch in whicheach automatic cutout has, between its input and output sides, twosuperposed externally accessible points for the interconnection with arespective winding of the summation current transformer.

Another object of the invention is to provide such a switch in which theside walls of each cutout are formed with openings for passage of theends of the respective summation current transformer winding, theseopenings communicating with the connecting points.

For an understanding of the principles of the invenion, reference ismade to the following description of a typical embodiment thereof asillustrated in the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the Drawing:

FIG. 1 is a perspective view of two unipolar automatic cutouts orcircuit breakers combined to form a multipolar automatic cutout;

FIG. 2 is a perspective view of a summation current transformerillustrating the through windings; and

FIG. 3 is a perspective view of the unit having the current faulttesting part and the release part.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing, abipolar fault current protective switch, constituted by the partsillustrated in FIGS. 1, 2 and 3, comprises the unit 1 which contains afault current testing part and a release part, which have not beenshown, and is designed to receive the summation current transformer 2.Unit 1 is arranged to have connected therewith two unipolar automaticcutouts or circuit breakers 3 and 3a which are coupled mechanically witheach other and which have a common switch handle 4. Each automaticcutout has superposed connecting points 5 and 6. The upper connectingpoint 5 is provided for the external connection and has a clamping screw7 for the external conductor and a connecting lug 8 with a bore 9 forthe internal conductor.

The lower connecting point 6 is the end of a conductor rail or busoriginating from the inner circuit, and which is designed as aconnecting lug. Connecting lug 6 also is provided with a bore 9. Bothconnecting lugs 6 and 8 are seated on the apparatus wall of therespective automatic cutout 3,3a, in such a manner that the profile ismaintained with respect to the base of the automatic cutout.

In the range of the connecting points in cutouts 3 and 3a, there arefomied openings 10 in the side walls of each cutout, for the shunt orcross connections to the unit 1. The ends 11 of through windings 12 ofsummation current transformer 2 are led through or inserted throughthese housing openings and inserted, from the inside, through the bores9 of connecting lugs 6 and 8. The respective winding ends are solderedor welded to the connecting lugs from the exterior in a simple manner.The openings 10 in the side walls are marked by grooves which are sodesigned that the openings can be broken open, when required. In orderto obtain protection against contact, the connecting lugs 5 and 6 can beprotected by a cover strip of insulating material, which has not beenshown.

When the ends 11 of through windings 12 of summation current transformer2 have been secured in the connecting lugs 6 and 8, and casing 1, whoseprofile in side elevation is identical with the side elevation profileof the circuit breakers 3 and 3a, is bolted to the circuit breakers,summation transformer 2 is received within and enclosed by the casing orunit 1.

While a specific embodiment of the invention has been shown anddescribed in detail to illustrate the application of the principles ofthe invention, it will be understood that the invention may be embodiedotherwise without departing from such principles.

We claim:

1. A multipolar fault current protective switch comprising, incombination, a summation current transformer; a unit including a modularhousing containing a fault current testing part and a release part andarranged to receive said summation current transformer; and relativelynarrow-type automatic cutouts each including a respective modularhousing and arranged for coupling mechanically and electrically withsaid unit in modular juxtaposed relation therewith and with each other;each automatic cutout having two superposed connecting points,accessible externally of the front wall of the respective housing, forinterconnection with a respective winding of said summation transformer;

each cutout having side walls with openings communicating interiorly ofthe respective housing with said connecting points, said openingsproviding for insertion of the ends of the respective transformer intothe respective housing and into the connecting points thereof forelectrical connection thereto from the exterior of the front wall of therespective housing, to electrically interconnect the respective twosuperposed connecting points.

2. A multipolar fault current protective switch, as claimed in claim 1,in which each connecting point comprises a respective terminal having abore for receiving a conductor.

3. A multipolar fault current protective switch, as claimed in claim 2,in which each lower connecting point is the end of an electricallyconductive rail forming part of the internal circuit of the respectivecutout.

4. A multipolar fault current protective switch, as claimed in claim 2,in which each of said terminals is seated in a recess in the wallstructure of the associated cutout so as to be completely within theexternal profile of the associated cutout.

5. A multipolar fault current protective switch, as claimed in claim 4,in which said openings are formed in side walls of the respectivecutouts and are in the form of knock-out openings delineated on theexternal surface of the associated side wall.

6. A multipolar fault current protective switch, as claimed in claim 2,including protective cover strips extending over said terminals.

7. A multipolar fault current protective switch, as claimed in claim 2,in which each upper connecting point is a screw terminal threaded into aconnecting lug having said bore, for engagement with an external circuitconductor inserted into the associated connecting lug.

1. A multipolar fault current protective switch comprising, incombination, a summation current transformer; a unit including a modularhousing containing a fault current testing part and a release part andarranged to receive said summation current transformer; and relativelynarrow-type automatic cutouts each including a respective modularhousing and arranged for coupling mechanically and electrically withsaid unit in modular juxtaposed relation therewith and with each other;each automatic cutout having two superposed connecting points,accessible externally of the front wall of the respective housing, forinterconnection with a respective winding of said summation transformer;each cutout having side walls with openings communicating interiorly ofthe respective housing with said connecting points, said openingsproviding for insertion of the ends of the respective transformer intothe respective housing and into the connecting points thereof forelectrical connection thereto from the exterior of the front wall of therespective housing, to electrically interconnect the respective twosuperposed connecting points.
 2. A multipolar fault current protectiveswitch, as claimed in claim 1, in which each connecting point comprisesa respective terminal having a bore for receiving a conductor.
 3. Amultipolar fault current protective switch, as claimed in claim 2, inwhich each lower connecting point is the end of an electricallyconductive rail forming part of the internal circuit of the respectivecutout.
 4. A multipolar fault current protective switch, as claimed inclaim 2, in which each of said terminals is seated in a recess in thewall structure of the associated cutout so as to be completely withinthe external profile of the associated cutout.
 5. A multipolar faultcurrent protective switch, as claimed in claim 4, in which said openingsare formed in side walls of the respective cutouts and are in the formof knock-out openings delineated on the external surface of theassociated side wall.
 6. A multipolar fault current protective switch,as claimed in claim 2, including protective cover strips extending oversaid terminals.
 7. A multipolar fault current protective switch, asclaimed in claim 2, in which each upper connecting point is a screwterminal threaded into a connecting lug having said bore, for engagementwith an external circuit conductor inserted into the associatedconnecting lug.